Re-characterization of architectural style of reinforced concrete building facades by exterior seismic strengthening

Recent earthquakes in Turkey have shown the poor seismic performance of reinforced concrete residential buildings. This led to widespread utilization of several strengthening methods, each of which is convenient in different aspects. However, what is required to apply any of these methods is to evacuate the building in question, since the interruptions are mostly within the building and to the structural members. In this article, a method is introduced for external strengthening of typical reinforced concrete buildings that represent the majority of the built environment in Turkey. The method suggests addition of shear walls, which are connected to each other by means of reinforced concrete diaphragms on two separate floor levels and to the existing external columns and floor system at corners of the building. The advantage of shear walls in seismic performance is already known; however, this article discusses the feasibility of the proposed method in terms of architectural viewpoint, since the method unavoidably covers great modifications on the architectural form of the building. As a whole, this external strengthening method provides a typical facade resemblance by means of additional structural members without emptying the building.     

CFRP加固钢筋混凝土震损短柱的抗震性能研究

在国内外历次地震中,均有钢筋混凝土短柱发生剪切破坏的实例,现存结构中也有大量的短柱存在。为了探索有效的钢筋混凝土短柱的加固方法,本文进行了4个短柱在低周反复荷载作用下的试验。其中3个试件在低周反复荷载作用下开裂后持荷用CFRP加固,另一个试件不进行任何加固。试验结果表明,开裂钢筋混凝土短柱在用CFRP加固后,不仅增加了短柱的极限承载力,还可以避免脆性破坏。研究还表明,CFRP的加固方法还可用来修复钢筋混凝土短柱。     

Commonly encountered seismic design faults due to the architectural design of residential buildings in Turkey

The 17 August 1999 and 12 November 1999 earthquakes in Western Anatolia provided undesirable field evidence that most of the low story residential reinforced concrete buildings have very poor earthquake resistance. Architectural design faults negatively affect the structural behavior of buildings. In Turkey, earthquake-resistant design is considered to be exclusively within the field of responsibility of structural engineers. As a result, architects and especially students of architecture are not well informed about the effect of their design decisions on the seismic performance of the buildings. Structural damages in collapsed buildings demonstrate that most of the design faults that lead to destruction of buildings are due to architectural decisions. This paper intends to present the concept of earthquake-resistant design in a comprehensible format for the architects and builders, therefore aims to contribute to the efforts of creating a better awareness of earthquake resistant building design.     

Seismic behavior of tall buildings using steel–concrete composite columns and shear walls

For the seismic design of tall building structures, the behavior under severe earthquakes should be carefully considered and the upper limit of inter‐story deformations are often defined by the design codes. To improve the performance of structures under severe earthquakes, composite structural members, including steel reinforced column and steel plate reinforced shear wall, are often adopted. In the present work, the seismic behavior of tall buildings using steel–concrete composite columns and shear walls is investigated numerically. Fiber beam–column element models and multilayer shell models are adopted to establish the finite element model of structure, and the material nonlinearities are described by the plasticity and damage models. The accuracy of the developed models is verified by the experimental results of a single shear wall. Systematic numerical simulations are performed for the tall building structures subjected to different earthquakes. The comparative study indicates that the nonlinear redistribution of internal forces plays a very important role for the performance of tall buildings under severe earthquakes.     

Numerical simulation of squat reinforced concrete wall strengthened by FRP composite material

The advanced design rules and the latest known earthquakes, have imposed a strengthening of reinforced concrete structures. Many research works and practical achievements of the application of the external reinforcement by using FRP composite materials have been particularly developed in the recent years. This type of strengthening seems promising for the seismic reinforcement of buildings. Among of the components of structures that could affect the stability of the structure in case of an earthquake is the reinforced concrete walls, which require in many cases a strengthening, especially in case where the diagonal cracks can be developed. The intent of this paper is to present a numerical simulation of squat reinforced concrete wall strengthened by FRP composite material (carbon fiber epoxy). The intent of this study is to perform finite element model to investigate the effects of such reinforcement in the squat reinforced concrete walls. Taking advantage of a commercial finite element package ABAQUS code, three-dimensional numerical simulations were performed, addressing the parameters associated with the squat reinforced concrete walls. An elasto-plastic damage model material is used for concrete, for steel, an elastic-plastic behavior is adopted, and the FRP composite is considered unidirectional and orthotropic. The obtained results in terms of displacements, stresses, damage illustrate clearly the importance of this strengthening strategy.     

某校舍综合楼的抗震鉴定与加固设计

汶川地震以后,国务院成立全国中小学校舍安全工程领导小组,统一领导和部署中小学校舍安全工程。在全国范围实施校舍安全工程,全面改善中小学校舍安全状况,在全国中小学校开展抗震加固、提高综合防灾能力建设,使学校校舍达到重点设防类抗震设防标准。根据中小学校舍抗震鉴定加固工程委员会的要求,需对原结构按照新规范进行全面检测和抗震鉴定,本文结合某工程实例,采用一种较好的抗震加固方法—钢筋混凝土板墙加固法。它具有较大刚度、强度,有良好的变形和延性,对提高抗震能力有显著作用,施工快,综合效益好。对加固方法做了一个全面的论述,以供今后的类似工程参考。     

兰州大学图书馆楼扩建与加固的技术处理

结合兰大图书馆楼工程实例 ,就其改扩建工程中采用的技术处理作一些介绍。着重介绍了旧建筑物与共享大厅的连接 ,塔楼加高改造及粘钢增强钢筋混凝土梁抗剪能力的技术处理 ,可供同类工程参考     

钢筋混凝土剪力墙结构施工技术

经过对工程项目中钢筋混凝土剪力墙结构的施工总结,从剪力墙的模板工程施工、钢筋的安装和定位、混凝土的施工质量控制、门窗洞口处施工注意事项等方面探讨了高层建筑钢筋混凝土剪力墙结构施工的技术控制要点。     

某物流工程加固方法的综合应用

简述了钢筋混凝土结构中常用的加固方法及其适用范围，通过具体工程实例，介绍了增大截面和粘贴碳纤维等加固方法在某物流工程中的综合应用，并提出了设计施工建议，以确保建筑物使用安全。     

国家民航总局办公楼加固改造设计

民航总局办公楼建于60年代初,分别由14,11和9层的三个装配整体式框架结构组成。唐山地震时各单体建筑曾发生过相互碰撞。尽管使用年限长久,局部有损伤,但经技术鉴定和方案论证,该楼通过改造加固,可以满足现行规范的抗震和正常使用等方面的要求。加固改造采用加设剪力墙、基础和梁柱加大断面或粘钢、板粘碳纤维的加固方法,将弱框架结构改造成框剪结构体系,效果良好。     

四川德阳某学校实训大楼的抗震加固设计

以四川省德阳市商贸学校实训大楼抗震加固设计为例,结合检测情况及改造要求采用加大截面法进行钢筋混凝土框架结构抗震加固设计,从而提高了建筑物的抗震性能,满足了房屋的安全使用要求,为加固工程设计提供了借鉴和参考。     

配筋砂浆带加固土坯墙体的抗震性能研究与实践

对于土坯墙承重结构,由于材料强度低、变形能力差,房屋抗震性能严重不足,目前是西部农村的主要危房改造对象。为提高土坯墙承重房屋的安全性,采用十形和X形两种配筋砂浆带加固方法对土坯墙体进行加固。通过对3片墙体的水平低周反复加载试验,分析配筋砂浆带用于抗震加固土坯墙片的受力特性与破坏形态,对两种加固效果进行了对比分析。研究结果表明：配筋砂浆带加固方法可以有效提高土坯墙片的抗震性能,采用十形配筋砂浆带加固的土坯墙具有良好的变形能力,采用X形配筋砂浆带加固的土坯墙水平受剪承载力得到大幅提高。配筋砂浆带加固方法在甘肃省农村危房改造工程中的应用实践证明,该方法操作方便,具有良好的经济效益。     

Strengthening of RC T-section beams with low strength concrete using CFRP composites subjected to cyclic load

Various methods are developed for strengthening reinforced concrete beams against shear. Nowadays, external bonding of different composite members to RC beams was very popular and successful technique internationally. This study presents test results on strengthening of shear deficient RC beams by external bonding of carbon fiber reinforced polymer (CFRP) straps. Six RC beams with a T-section were tested under cyclic loading in the experimental program. Width of the CFRP straps, arrangements of straps along the shear span, and anchorage techniques that were applied at the ends of straps were the main parameters that were investigated during experimental study. Shear deficient beams with low strength concrete were strengthened by using CFRP straps for obtaining ductile flexural behavior. The test results confirmed that all CFRP arrangements improved the strength, stiffness and energy dissipation capacity of the specimens significantly. The failure mode and ductility of specimens were proved to differ according to the CFRP strap width and arrangement along the beam. Experimental results were compared with the analytical approaches that were suggested by ACI-440 Committee Report.     

钢板组合构造柱及嵌筋法在宿舍楼抗震加固中的应用

新疆地区中小学学生宿舍楼的结构大多为砌体结构,由于砌体结构存在强度低、易脆性破坏、整体性差等缺陷,因此对砌体结构宿舍楼的抗震加固显得十分必要。本文通过一个实际工程介绍了砌体房屋抗震鉴定及加固的一般过程,并提出了一种用钢板组合构造柱代替钢筋混凝土构造柱及墙体后嵌水平钢筋的加固方案。     

民国某仿木构钢筋混凝土结构的加固设计

民国仿木构钢筋混凝土建筑是具有典型中国特色的建筑遗产,大多承载着重要历史文化信息,对其加固修缮应在符合文物保护原则的前提下合理进行结构性能和耐久性的提升。结合浙江某民国仿木构钢筋混凝土结构加固修缮实例,较全面地讨论了仿木构钢筋混凝土结构类型的民国建筑在加固设计中应考虑的若干关键问题,包括检测鉴定、计算分析、混凝土构件加固及墙体加固等,介绍一些有效的解决办法,如钢丝网聚合物砂浆抹面法加固混凝土柱和梁、钢筋网聚合物砂浆抹面法加固混凝土板等,能满足后续使用年限30年的要求,可供同类建筑物加固修缮参考。     

汶川地震中宝鸡市中小学建筑破坏的调查及震害分析

通过对汶川地震及其系列余震造成的宝鸡市中小学建筑震害的调查,总结了各类学校建筑(包括砖混、砖木和土木结构)的地震破坏形式,简要分析了其破坏原因,同时对受损房屋进行了分类并提出了加固处理措施。此外,还提出了提高中小学建筑抗震性能的措施,为今后学校建筑的设计提供了一定的依据。     

钢筋混凝土保护层厚度取值的建议

本文在综合分析工程调查与试验结果的基础上,阐述了在一般使用条件下的混凝土碳化与钢筋锈蚀的主要影响因素,及其对钢筋混凝土结构产生的主要危害。考虑结构耐久性的要求,就保护层最小厚度的取值和保证混凝土施工质量的相应措施,提出了建议。     

基于Perform-3D剪力墙的弹塑性数值分析

钢筋混凝土剪力墙是高层结构抗震的主要抗侧力构件之一。针对其弹塑性行为的特点,目前已发展了多种微观和宏观分析模型。基于Perforn-3D程序中的纤维墙单元,对3个典型的剪力墙试验构件进行低周反复数值模拟,并对材料的本构和建模参数进行了详细的讨论。计算结果表明,该分析方法能够较好地从宏观角度模拟剪力墙的弹塑性行为,适用于高层建筑结构的整体弹塑性分析和抗震性能评估。     

型钢混凝土短柱受剪承载力计算模型研究

型钢混凝土（steel reinforced concrete,SRC）结构因承载力高、刚度大、耐火及耐久性能好等优点在高层及超高层建筑中被广泛使用,其中SRC柱作为主要竖向承重及抗侧力构件,其在地震作用下承载能力直接影响整体结构在地震作用下的响应。目前,对于SRC短柱受剪承载力计算方法有待深入研究,而各国规范或规程中使用的基于强度叠加法的半经验-半理论计算公式缺乏明确的力学模型作为支撑。为此,利用SRC短柱中钢筋混凝土（reinforced concrete,RC）部分与型钢及其内部混凝土部分的剪切变形相互关系,确定了RC部分与型钢及内部混凝土组合体到达其受剪承载力的先后顺序,并以此提出了基于强度叠加法的SRC短柱受剪承载力计算模型,并将该模型及现行规范的计算结果与文献记载的66个发生剪切破坏的SRC短柱的试验结果进行了对比。结果表明：模型可准确预测文献记载的66个发生剪切破坏的SRC短柱的受剪承载力;模型中对RC部分与型钢及其内部混凝土部分剪切变形的考量可准确定义SRC短柱在峰值荷载时的剪力分配机制,在实际工程设计时可依此判断SRC短柱中RC部分与型钢及其内部混凝土部分的承载力利用率,使SRC短柱的受剪承载力最大化。     

Predicting ductility demands on reinforced concrete moment‐resisting frames for moderate seismicity

The seismic responses of existing reinforced concrete‐framed buildings that are primarily designed and detailed to resist onerous combinations of gravity and wind loads are simulated for the conditions of moderate seis micity. A procedure is established for relating the non‐seismic and seismic behaviours of structures. By using the proposed procedure, the theoretical curvature ductility demands of ordinary reinforced concrete moment‐resisting frames can be evaluated. It has been shown that shear response of the frames due to earthquakes is dominant and adopted as a basis for estimating ductility demands. It is concluded that for low‐rise ordinary moment‐resisting framed buildings in regions liable to low or moderate sesimicity, the reduction factor suggested in the 1997 UBC might not be appropriate for use in the seismic analysis of these structures. Copyright © 2005 John Wiley & Sons, Ltd.